1. Field of the Invention
The present invention relates to a method of making a nitride semiconductor laser, a method of making an epitaxial wafer, and a nitride semiconductor laser.
2. Related Background Art
Patent document 1 (Japanese Patent Application No. 9-144291) discloses a method of forming a flat continuous GaN film. In the initial stage of deposition of the GaN film, the deposition for the GaN film is carried out under a film formation condition in the presence of a stoichiometrical excess amount of gallium (Ga). In the subsequent stage, the film is deposited under a film formation condition in the presence of a stoichiometrical excess amount of nitrogen (N). Over these stages, Ga and N are supplied onto a substrate in parallel.
Patent document 2 (Japanese Unexamined Patent Application Publication No. 2000-49104) discloses a method of forming a satisfactory monocrystalline GaAsN. In this deposition process of a GaAsN mixed crystal having a miscibility gap composition, the GaAsN mixed crystal is deposited by repeating the following: supply of Ga, nitriding, supply of Ga, and production of arsenide.
Patent document 3 (Japanese Unexamined Patent Application Publication No. 2000-216101) discloses a method of growing a GaInNAs compound semiconductor mixed crystal, which has an immiscible composition in a thermal equilibrium state. In the growth of GaInNAs compound semiconductor mixed crystal, the deposition of GaInNAs compound semiconductor mixed crystal is interrupted, and in the interrupt, a crystalline GaAs compound semiconductor thin film is deposited. GaAs compound semiconductor is composed of some of the constituent elements of the GaInNAs compound semiconductor mixed crystal, and has a miscible composition in a thermal equilibrium state.
Patent document 4 (Japanese Unexamined Patent Application Publication No. 2004-165571) discloses a method of forming a nitride thin film through deposition of a high-quality atomic layer within a short time. In this method, raw material containing an organometallic gas is blown onto a substrate under an ammonic atmosphere of 1×10−3 to 1 Pa to form an elemental metal layer on the substrate. Subsequently, the blowing of raw material is interrupted to form a nitride thin film, that is, nitride of the elemental metal layer on the substrate.
Patent document 5 (Japanese Unexamined Patent Application Publication No. 2003-68660) discloses a method of making a nitride compound semiconductor layer through an organometallic vapor-phase epitaxy process. In this method, group III raw material, which contains a group III organo-metal material, is supplied intermittently onto a substrate while supplying nitrogen-containing gas onto the substrate.